U.S. Pat. No. 4,910,946 discloses an extensible combine header for harvesting small grain. Lateral header units are telescopically moveable with respect to a center unit. To allow a transportation of the cut crop as well as extension and retraction of the header, overlapping housing parts are provided and the auger core is formed like a telescope, whereas the auger flights are substantially loose and flexible on the core. Extension and retraction are accomplished by hydraulic cylinders.
It is known from EP A1 640 277 to combine three pick-up units to a single crop collecting assembly, whereas the pick-up units are vertically moveable with respect to each other and can be driven independent of each other and depending on a sensed velocity of a harvesting vehicle. The outer pick-up units can be tilted upwardly to assume a transport position. Furthermore the pick-ups can be of the tine or of the belt type, whereas the belt may be flexible enough to allow said movement of the outer pick-up units. The collected crop is fed to a downstream baler.
The problem to be solved by this invention is seen in that said known pick-up can be operated only if windrows maintain always a given distance to each other.